The only special lines are the "Status"-Line and the 5th Pin. For normal operation, Status (Pin 2) is tied to Pin 1 (GND). An Open Pin 2 means either "Fan not present" or "Fan Failure". The 5th Pin may be a PWM-Control Signal for the Fan, but it is not necessary to connect it.

Pin
Number

Pin
Name

Description (may be empty)

1

GND

2

Status

Fan Present / Fan Failure

3

12 V

4

Sense

Standard Tachometry Signal

5

? PWM

possibly PWM-Control Signal, optional

Bridge Pin 1 and 2 to be able to connect normal Fans.

5pin CPU connectors letting pin 5 open. System complains on boot: Fan solution not sufficient. This means, that pin 5 has to be connected, but I it is not known what has to be connected there.